This invention generally relates to hinges and, more particularly, to bi-directionally operating hinges for use in electronic devices, including wireless phones, personal digital assistants, notebook computers, and the like.
In certain hinge applications, it is desirable to provide a hinge which can maintain a hinged member in an open position or a closed position. When the hinged member is in the open position, in certain applications, such as clamshell-style phones and notebook computers, it is desirable that the hinged member be held stably in position. It is also desirable in such applications that the hinge maintain the hinged member in a closed position relative to the device housing for storage and transport. Generally in such applications, the open position is set at a fixed, predetermined angle.
One known, relatively inexpensive, preassembled, self-contained, two-position hinge can hold a hinged member in a first, open position or a second, closed position relative to a device housing without imparting an axial load on the hinged member or the device housing, thereby resulting in a longer operating life. The hinge uses a cam surface and a cam follower urged toward the cam surface by a spring to hold either a closed position or an opened position between 130 degrees and 160 degrees relative to the device housing. The hinge pivots the hinged member about a single axis. Although extensively used in clamshell-style phones, this type of hinge has limited usefulness in applications which prefer a different minimum amount of torque for closing a device than for opening a device.
In another known hinge, a higher torque is required to pivot a hinged member in one direction than is required to pivot the hinged member in the other direction. The hinge, primarily used in notebook computers, pivots the hinged member about a single axis.
It is desirable to provide a hinge that stably maintains a hinged member in opened and closed positions and requires a higher torque to pivot in one direction than the other direction, the hinge also providing for bi-directional opening of the hinged member.